The procedure of Anteroposterior Tooth Contact Adjustment (APTCA) in Orthodontic patients

Orthodontic relapse is the major concern in both adolescent and adult orthodontic treatment. The causes of orthodontic relapse are reported to be of various origins. Functional diagnostic procedures allow to report the presence of disturbances in temporomandibular joint functioning, chewing muscle functioning and tooth contacts. The T-scan computerized occlusal analysis is aimed to diagnose the presence of tooth contacts that contribute to the overall imbalance in the occlusal pattern, the presence of force outliers which contribute to excessive teeth load and the timing characteristics of the functioning occlusion. The procedure of Anteroposterior tooth contact adjustment (APTCA) was worked out to analyze the presence of factors contributing to the anterior teeth movements after the completion of orthodontic treatment and subsequently to diminish the risk of the orthodontic relapse caused by these tooth contacts. Research Article The procedure of Anteroposterior Tooth Contact Adjustment (APTCA) in Orthodontic patients Romanova Julia1 and Koval Svitlana2* 1Department of Therapeutic Dentistry, Odessa National Medical University 2Department of Therapeutic Dentistry, Odessa National Medical University, Private Orthodontic Clinic ‘’SK Dental», Odessa, Ukraine Dates: Received: 05 June, 2017; Accepted: 21 June, 2017; Published: 23 June, 2017 *Corresponding author: Koval Svitlana, MSc, Orthodontist, Department of Therapeutic Dentistry, Odessa National Medical University, Private Orthodontic Clinic SK Dental, Odessa, Ukraine, Tel: +00380677661463; Email: https://www.peertechz.com


Introduction
Orthodontic relapse is the main concern regarding the stability of orthodontic treatment outcome. Various causes were reported in the literature to contribute to orthodontic relapse [1,2]. Different malocclusion types show various prevalence of tendency to relapse [3,4], moreover, different orthodontic treatment techniques can predispose to post treatment tooth movements [5]. Both type of retention appliance and the retention protocol are considered to be the main contributing factors. Both occlusal contacts are targeted during orthodontic relapse examination [6][7][8] and electromyographic activity of chewing muscles [9].
Occlusal relationships were reported to cause tooth movements after the completion of orthodontic treatment [10,11] as well as signs and symptoms of temporo-mandibular dysfunction [12,13]. T-scan occlusal analysis (Tekskan, USA) was used to analyze occlusal relationships [14] and the distribution of forces during functional jaw movements [8,9,[15][16][17][18]. Detailed time report can be acquired as well as the duration of tooth contacts in different jaw movements and positions with the use of T-scan occlusal analysis. T-scan computerized occlusal analysis is currently the only procedure which can be used to calculate the amount of relative force and the duration of contacts along the dental arches.
We have developed a T-scan based occlusal analysis procedure which can be used to reveal contacts which contribute to orthodontic relapse after the completion of treatment.  in the case reports [10,11], is potentially prone to cause either buccal inclination of anterior teeth, or their rotation.
The APTCA procedure is implemented by disclusion time reduction, which was fi rst described by Kerstein [19,21], in the region on posterior teeth, both maxillary and mandibular. First patient is asked to bite on the sensor in his centric occlusion and then slightly move to canine edge-to-edge contact ( Figure 4).
The recording is then analyzed and the DT is checked ( Figure   5). DT should not exceed 0,5 seconds [20]. Then the patient is asked to occlude his teeth in centric occlusion with green occlusal paper between his teeth. The excursive movement is afterwards performed with the use of red occlusal paper to mark excursive contacts. The method implements two colors of occlusal paper to mark centric occlusal contacts in green and excursive contacts in red. Red marks are easily recognizable and can be removed according to canine guidance scheme.
The aim of APTCA is to achieve pure canine guidance in 0,5 seconds, eliminating posterior excursive contacts primarily.
These contacts are consequently removed after each recording.
The patient performs excursive movement with a sensor, paper marks are checked in the mouth, then excursive contacts removed on posterior teeth, and again the patient is asked to bite the sensor. It may take up to 8-10 cycles of repeated adjustment to achieve proper DT on the working side. The same procedure is done on the opposite side, when the patient performs lateral movement on the opposite working side.
Great emphasis is put on eliminating working contacts on the teeth posterior to ipsilateral canine. If teeth are already severely worn or sensitivity level is high, or canine is worn itself, canine`s restoration is essential to restore proper function and secure post treatment stability.
Excursive movements are performed on each side, both left and right. (Figure 6). Disclusion time is analyzed and compared to the estimated normal time of 0,5 seconds. Any contacts on both working and non-working sides which tend to prolong the discussion time should be eliminated.    Protrusion movement is of a great value as well (Figure 7).
The discussion time in protrusive movements is also expected to be not more than 0,5 seconds (Figure 8). Any contacts tending to prolong discussion time in protrusive movement will tend to move the upper anterior teeth in buccal direction.
The distribution of posterior contacts causes selective infl uence on anterior teeth.

Conclusion
Patients` concern about orthodontic stability raises the point of seeking different approaches to fi nishing orthodontic cases. Both different kinds of orthodontic retainers and settling procedures try to establish optimum and stable results. This chapter introduces the concept of functional corrections by T-scan III occlusal analysis system. The newly developed anteroposterior tooth contact adjustment (APTCA) procedure decreases the risk of orthodontic relapse caused by posterior excursive contacts. The implementation of the APTCA procedure is outlined and the main characteristics of T-scan III software are given. The APTCA procedure is aimed to secure orthodontic treatment stability and eliminate any functional interferences, which may later cause muscle and TMJ dysfunctions.